Francesco Redi: Founder of Experimental Biology

Engraving portrait of Francesco Redi
Bettmann Archive / Getty Images

Francesco Redi was an Italian naturalist, physician, and poet. Besides Galileo, he was one of the most important scientists who challenged Aristotle's traditional study of science. Redi gained fame for his controlled experiments. One set of experiments refuted the popular notion of spontaneous generation—a belief that living organisms could arise from nonliving matter. Redi has been called the "father of modern parasitology" and the "founder of experimental biology".

Fast Facts

Birth: February 18, 1626, in Arezzo, Italy

Death: March 1, 1697, in Pisa Italy, buried in Arezzo

Nationality: Italian (Tuscan)

Education: University of Pisa in Italy

Published Works: Francesco Redi on Vipers (Osservazioni intorno alle vipere), Experiments on the Generation of Insects (Esperienze Intorno ​alla Generazione degli Insetti), Bacchus in Tuscany (Bacco in Toscana)

Major Scientific Contributions

Redi studied venomous snakes to dispel popular myths about them. He demonstrated that it is not true that vipers drink wine, that swallowing snake venom is toxic, or that venom is made in a snake's gallbladder. He found that venom was not poisonous unless it entered the bloodstream and that the progression of venom in the patient could be slowed if a ligature was applied. His work paved the foundation for the science of toxicology.

Flies and Spontaneous Generation

One of Redi's most famous experiments investigated spontaneous generation. At the time, scientists believed in the Aristotelian idea of abiogenesis, in which living organisms arose from non-living matter. People believed rotting meat spontaneously produced maggots over time. However, Redi read a book by William Harvey on generation in which Harvey speculated that insects, worms, and frogs might arise from eggs or seeds too tiny to be seen. Redi devised and performed the now-famous experiment in which six jars, half left in open air and half covered with fine gauze that permitted air circulation but kept out flies, were filled with either an unknown object, a dead fish, or raw veal. The fish and veal rotted in both groups, but maggots only formed in the jars open to air. No maggots developed in the jar with the unknown object.

He performed other experiments with maggots, including one where he placed dead flies or maggots in sealed jars with meat and observed living maggots did not appear. However, when he placed living flies were placed in a jar with meat, maggots did appear. Redi concluded maggots came from living flies, not from rotting meat or from dead flies or maggots.

The experiments with maggots and flies were important not only because they refuted spontaneous generation, but also because they used control groups, applying the scientific method to test a hypothesis.


Redi described and drew illustrations of over one hundred parasites, including ticks, nasal flies, and the sheep liver fluke. He drew a distinction between the earthworm and the roundworm, which were both considered to be helminths prior to his study. Francesco Redi performed chemotherapy experiments in parasitology, which were noteworthy because he used an experimental control. In 1837, Italian zoologist Filippo de Filippi named the larval stage of the parasitic fluke "redia" in honor of Redi.


Redi's poem "Bacchus in Tuscany" was published after his death. It is considered among the best literary works of the 17th century. Redi taught the Tuscan language, supported the writing of a Tuscan dictionary, was a member of literary societies, and published other works.


Redi was a contemporary of Galileo, who faced opposition from the Church. Although Redi's experiments ran contrary to the beliefs of the time, he did not have the same sort of problems. This may well have been because of the different personalities of the two scientists. While both were outspoken, Redi did not contradict the Church. For example, in reference to his work on spontaneous generation, Redi concluded omne vivum ex vivo ("All life comes from life").

It's interesting to note that despite his experiments, Redi believed spontaneous generation could occur, for instance, with intestinal worms and gall flies.


Altieri Biagi; Maria Luisa (1968). Lingua e cultura di Francesco Redi, medico. Florence: L. S. Olschki.

mla apa chicago
Your Citation
Helmenstine, Anne Marie, Ph.D. "Francesco Redi: Founder of Experimental Biology." ThoughtCo, Sep. 18, 2020, Helmenstine, Anne Marie, Ph.D. (2020, September 18). Francesco Redi: Founder of Experimental Biology. Retrieved from Helmenstine, Anne Marie, Ph.D. "Francesco Redi: Founder of Experimental Biology." ThoughtCo. (accessed June 7, 2023).